This is a competing renewal of a training program designed to prepare highly qualified post-doctoral fellows for research careers in respiratory biology and disease pathogenesis. In this program, we will encourage applications of MD and PhD candidates from various sources (Clinical &Basic Science Departments) emphasizing a nationwide competition. MD trainees are allowed to enter this program only after having completed the clinical requirements for Board eligibility. Optimal research training is achieved by protecting the trainees'time to allow their efforts to be dedicated to research. Training is mentor-based and is enriched by didactic courses and by interactions with a broadly-based faculty. The faculty were chosen based on ongoing research productivity, significant extramural support and availability and commitment to serve as mentors. They also belong to research spheres identified as important in respiratory disease processes: including the cell biology, molecular biology and genetics of immunology, inflammation and tissue remodeling, and clinical epidemiology and biostatistics. Because of the wide spectrum of strong laboratories at Yale and the institutional nature of this proposal, 8 post-doctoral positions are requested per year. The duration of the program will be a minimum of 2 years. Trainee progress will be carefully evaluated and productivity monitored by each mentor, a Training Advisory Committee and the Program Director. The uniqueness of this program stems from a) the truly institutional nature of this grant involving 3 Schools, 3 Clinical Depts (Pediatrics, Internal Medicine and Pyschiatry) and 10 Basic Science Depts;b) the strong interactions that exist between the clinical and basic science faculty on this program and c) the training track record of the resource faculty. Through this program, we expect to entice, train, and prepare future leaders in pulmonary research in academic pediatrics, internal medicine and basic science arenas.